1. Field
The present invention relates generally to performance measurement techniques and, more specifically, to measurement of performance of an execution thread within a symmetric multi-threading (SMT) system.
2. Description
It is a general practice to increase the computational performance by organizing parallel program execution. There are a number of methods to achieve this, including, but not limited to, out-of-order instruction execution, multiple data operands, shared memory multi-processor systems, distributed computations, and so forth. One of the popular and relatively inexpensive approaches is to combine multiple execution cores within one physical processor, or even provide separate execution state containers and control logic to share multiple processing units of a physical processor. The latter statement is applicable, for example, to the Hyper-Threading technology commercially available from Intel Corporation, which provides better utilization of various execution units incorporated in a processor.
Measurement of a processor's (program's) performance is one of the main tasks to be solved when building an efficient computational system. For single processor systems, performance monitoring is a matter of correctly written software, given that the processor (or other hardware components) provides the necessary resources. The performance monitoring task may be more difficult for SMT systems: performance monitoring hardware support may vary considerably, and the interaction between hardware and software parts of performance monitoring system becomes more complicated.
Possible difficulties that can arise include the lack of performance monitoring resources (e.g., performance counters) to monitor the activity of all processing units (e.g., logical threads or processors) within a physical package, and no hardware support of asynchronous and independent measurements performed on a per-thread (per-logical processor/unit) basis.
Therefore, a need exists for the capability to efficiently monitor the performance of multi-threading systems taking into account the possible lack of hardware resources.